[aprssig] EMI Help

Rich Osman Rich at osman.com
Sat Aug 14 08:42:37 EDT 2004

I'd be more worried about ground loops than EMI.  HOw is the GPS 
connected, and equally important, how is the radio connected to the 
display, power and antenna?

Also, on your earlier question about regulators:  Calculate a series 
resistor that provides the drop you need at maximum currrent for 10 
volts input.  If the regulator is pulling little current, the input will 
rise but you don't care, it won't be dissipating much power.  

Were it me, I'd do something like this 

Andrew Rich wrote:

>Ok I built a GPSiiLCD display. works fine on the bench
>throw it in the car , drive off down the road
>works for about 5 kms
>random characters start to creep in.
>then the whole thing just gets worse - until it unusable - grabage all over
>the screen
>even ran it on battery and 12volts from the car .
>the project is in a plastic case
>any body had probs with hamhuds and EMI ?
>i have grounded the shield from the gps to the unit
>maybe i can try some caps across the bus lines ?
>Any body an expert on EMI ?
>Cheers Andy VK4TEC
>aprssig mailing list
>aprssig at lists.tapr.org

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